’Nature’ is one of the most problematic and complex words of our culture. Its meaning diverges both in everyday and specialist use, but certain dominant meanings also create expectations as to the meaning of the word. Often ‘nature’ is understood as the nonhuman environment. Nevertheless, in the same context the meaning of the word may alter, directing the whole discussion to another direction. The diversity of meanings on the one hand, and the central cultural role of the word itself afford possibilities to take advantage of changes of meaning. Such problems with ‘nature’ are apparent in a multitude of contemporary debates over issues like gene technology, explanations of human behavior, sexuality or climate change. Naturalness and unnaturalness of these phenomena are everyday forums for struggles of definition. The problem of ‘nature’ is thus inevitably linked to questions of values, norms and power. The main aim of this study is to develop and test tools that might aid us in understanding the multiple meanings of ‘nature’ and their application. Contemporary debates and the accompanying expectations are however so close to us that it is hard to perceive such changes. Thus this study approaches the issue through a historical example. The object of inquiry is Jean-Jacques Rousseau’s book "Discourse on the Origin and the Foundations of Inequality Among Men" (Discours sur l’Origine et les Fondements de l’Inégalité parmi les Hommes, 1755). It is a classic of philosophy, anthropology, political history and many other fields. ‘Nature’ is undoubtedly Rousseau’s most important philosophical term, and its meaning in this book has been debated for decades. For this study it is especially intriguing that Rousseau tried with his Discourse to criticize earlier and contemporary philosophers and the societies of his time. This study thus looks at the rhetoric of ‘nature’ both in Rousseau’s time and in the later commentaries. In his novel reading Ville Lähde emphasizes that the changes in the meaning of ‘nature’ were an essential feature of Rousseau’s philosophy. He investigates the Discourse in light of four distinct philosophical motives and illuminates how the changes in the meaning of ‘nature’, even the apparent contradictions that have baffled Rousseau-scholars, can be understood through the shifts in philosophical motives. Rousseau’s speculative narrative of the history of humanity is a literary tool which allows him to 1) criticize other philosophers, 2) attack the urbanizing contemporary societies, 3) explore the constitution of humanity and 4) construct his own political philosophy. This interpretation shows how Rousseau was able to challenge reified ways to understand human nature, legitimacy of certain social structures or the nature of inequality with these changes of meaning. Investigating the case of Rousseau helps us not only to clarify the conundrums in contemporary debates, it also teaches that challenging the assumption of conceptual unity can clear the terrain for novel thought.